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Mohamed Hamidou

Publications and source records attributed to Mohamed Hamidou.

12 recordsLinked to original sources
PubMed2007

Expression and release of soluble HLA-E is an immunoregulatory feature of endothelial cell activation.

Human leukocyte antigen (HLA)-E belongs, with HLA-G and HLA-F, to the non-classic major histocompatibility complex (MHC) class I (Ib) molecules, broadly defined by a limited polymorphism and a restricted pattern of cellular expression. In contrast to HLA-G, the expression and function of HLA-E and HLA-F in physiologic and pathologic processes remain poorly established. In the present study, we show that HLA-E protein expression in normal human nonlymphoid organs is mainly restricted to endothelial cells (ECs). HLA-E is also basally expressed by B and T lymphocytes, natural killer (NK) cells and by macrophages. We demonstrate that tumor necrosis factor alpha (TNFalpha), interleukin-1beta (IL-1beta), and interferon gamma (IFNgamma) up-regulate the cell-surface expression of HLA-E on ECs in vitro and induce the release of soluble HLA-E (sHLA-E). HLA-E up-regulation protects IFN-gamma-activated ECs from NK-mediated cell lysis, while sHLA-E protects bystander cells. Finally, sHLA-E is not detected in normal sera, and increased serum levels correlate with disease activity in patients with antineutrophil cytoplasmic antibody-associated systemic vasculitis. Thus, HLA-E expression and release of sHLA-E are features of EC activation and emphasize immunoregulatory functions of the endothelium. The present identification of soluble HLA-E molecules may have important implications in understanding the pathogenesis of immune-mediated vascular diseases and for the diagnosis and monitoring of patients.

Base Sequence↗
PubMed2006

Neurological manifestations and neuroradiological presentation of Erdheim-Chester disease: report of 6 cases and systematic review of the literature.

Erdheim-Chester disease (ECD) is a rare, non-Langerhans form of histiocytosis of unknown etiology that affects multiple organs. We report 6 cases of ECD with neurological involvement and neuroradiological abnormalities on brain MRI. A literature review revealed 60 other cases of ECD with neurological involvement. We therefore analyzed 66 ECD patients with neurological involvement. Cerebellar and pyramidal syndromes were the most frequent clinical manifestations (41% and 45% of cases), but seizures, headaches, neuropsychiatric or cognitive troubles, sensory disturbances, cranial nerve paralysis or asymptomatic lesions were also reported. Neurological manifestations were always associated with other organ involvement, especially of bones (at least 86%) and diabetes insipidus (47%). Neurological involvement was responsible for severe functional handicaps in almost all patients and was responsible for the death of 6 of the 66 patients (9%). Neuroradiological findings could be separated into three patterns: the infiltrative pattern (44%), with widespread lesions, nodules or intracerebral masses, the meningeal pattern (37%), with either thickening of the dura mater or meningioma-like tumors, and the composite pattern (19%), with both infiltrative and meningeal lesions.

Adult↗
PubMed2004

[Non-justified visits to emergency units. Proposal of differentiated care].

OBJECTIVE: The number of visits to emergency units in public hospital settings in France increases every year. The adequation between admission to an SAU--Service d'accueil d'urgence (emergency unit) and the clinical status of the patient must be checked to improve handling upstream of the SAU. METHOD: A prospective study was conducted in the SAU of the University Hospital in Nantes to assess the proportion of patients who would benefit from direct hospitalisation, scheduled in a department of specialised or polyvalent medicine. RESULTS: This proportion was of 10%. Seventy-three percent of the patients were aged over 60. They were referred in 77% of cases by their treating physician and in 10.4% of cases by the physician on duty. Thirty-three percent of cases were non-specified organ diseases, 20% were dermatological affections, 12% broncho-pulmonary infections and in the same proportion rheumatological pathologies; other affections were rare. COMMENTS: The results of this study must be confirmed in a pilot study in which the general practitioner would refer any patient, that he would have sent to an SAU, directly to a medical department without passing through the SAU. To do so, using a cell phone, the practitioner would contact the hospital physician who would find a hospital bed. The impact of this new modality of hospitalisation on the SAU could be assessed in terms of the number of admissions avoided to the SAU.

Aged↗
PubMed2003

Treatment of polyarteritis nodosa and microscopic polyangiitis with poor prognosis factors: a prospective trial comparing glucocorticoids and six or twelve cyclophosphamide pulses in sixty-five patients.

OBJECTIVE: Because the optimal cyclophosphamide (CY) treatment duration for severe polyarteritis nodosa (PAN) without virus infection and microscopic polyangiitis (MPA) has not been established, we conducted a trial to compare the effectiveness of 6 versus 12 CY pulses given in combination with corticosteroids (CS). METHODS: Sixty-five (18 PAN, 47 MPA) previously untreated patients were randomized to receive 12 (n = 34) or 6 (n = 31) CY pulses combined with CS. PAN and MPA were histologically proven or met ACR criteria. All patients presented >or=1 factor of severity according to the five factor score (FFS). CY pulses were administered every 2 weeks for 1 month, then every 4 weeks. The end point of the study was the number of events (relapses and/or deaths) occurring in each group, analyzed according to an intention-to-treat strategy. The outcome was evaluated by Cox proportional hazards analysis. RESULTS: The baseline characteristics were similar for both groups. The mean (+/- SD) followup was 32 +/- 21 months. Survival analysis showed a significantly lower relapse probability (P = 0.02; hazards ratio [HR] = 0.34) and higher event-free survival (P = 0.02, HR = 0.44) for the 12 CY-pulse group while the mortality rates were not significantly different (P = 0.47). CONCLUSION: These results suggest that 6 CY pulses are less effective than 12 CY pulses to treat severe PAN and MPA, particularly with respect to the risk of relapses.

Adult↗
PubMed2003

Antisynthetase syndrome.

Seven autoantibodies directed against synthetases have been identified to date, the best known being anti-Jo1. Synthetases play a vital role in protein synthesis by catalyzing the acetylation of transfer RNAs (tRNAs). The most common form of antisynthetase syndrome is characterized by anti-Jo1 production, interstitial lung disease (ILD), inflammatory muscle disease, and, in many cases, fever, polyarthritis, Raynaud's phenomenon, and thick cracked skin on the fingers (mechanic's hands). The interstitial lung disease is generally of the "usual interstitial pneumopathy" type and shares similarities with idiopathic pulmonary fibrosis or scleroderma-related pulmonary disease. It governs the prognosis of the disease, being associated with an excess mortality rate of about 40%. The pathogenic mechanisms underlying antisynthetase syndrome remain unknown but may involve cell-mediated immunity. The treatment is not standardized. The ILD responds to glucocorticoids in some patients but requires other immunosuppressant drugs in others.

Antibodies, Antinuclear↗
PubMed2003

[Superantigens and vasculitis].

Superantigens are microbial products, that may activate in a polyclonal way, a high number of T lymphocytes bearing a specific VB segment of TCR; the best characterized are staphylococcal and streptogenic toxins. In a review of the literature, we summarize the role of these superantigens in primitive vasculitis, specially in Kawasaki syndrome and Wegener's granulomatosis. This pathogenic model highlights the complex relations between infection and autoimmunity.

Humans↗
PubMed2003

[Kikuchi-Fujimoto disease: two cases].

Kikuchi-Fujimoto disease, or necrotizing histiocyte lymphadenitis, is a rare anatomo-clinical entity of unknown cause. The patients present painful cervical lymph nodes, fever, and a flu-like syndrome, but the spontaneous course is usually favorable in six months. We observed two cases within six months in our unit. Both patients improved rapidly after diagnostic adenectomy.

Adenoidectomy↗
PubMed2003

[Antisynthetase syndrome. Three cases and a review of the literature].

Antisynthetase syndrome belongs to the idiopathic myositis group which includes pulmonary interstitial disease, arthritis, Raynaud's phenomenon, and mechanic's hands , associated with the anti-Jo1 antibody. We report three cases of antisynthetase syndrome, and review the clinical characteristics, and prognosis factors dominated by interstitial pneumonia.

Adult↗
PubMed2002

Role for vascular investigations in giant cell arteritis.

Giant cell arteritis is characterized by diffuse arterial inflammation that selectively involves the superficial temporal arteries but can occur in larger arteries. Various vascular investigations can assist in diagnosing and evaluating the extent of giant cell arteritis. Imaging techniques, mainly Doppler ultrasonography of the superficial temporal arteries, seem less reliable for the diagnosis than temporal artery biopsy, which is safe and remains indispensable. Investigations of larger arteries can detect asymptomatic stenotic lesions, which are common, particularly in the axillary and subclavian arteries. Involvement of the aorta can cause life-threatening dissection or aneurysmal rupture. Imaging techniques useful for diagnosing aortic involvement include ultrasonography, computed tomography, magnetic resonance imaging, and aortography. Although there is no standardized strategy for aortic lesion detection, helical computed tomography may be valuable.

Aortitis↗
PubMed2002

CD38 expression and secondary 17p deletion are important prognostic factors in chronic lymphocytic leukaemia.

CD38 expression and chromosomal abnormalities are novel prognostic factors in chronic lymphocytic leukaemia (CLL). However, their value remains undetermined. CD38 was evaluated in 123 patients and chromosomal aberrations in 111 cases with fluorescence in situ hybridization (FISH). CD38 expression was found in 27% of the cases. In addition, seven out of 32 CD38- patients became CD38+ during evolution of the disease. Chromosomal abnormalities included isolated 13q deletion (40%), 12q trisomy (14%), 11q deletion (without 17p deletion) (14%) and 17p deletion (7%). CD38 expression was significantly associated with Binet stages B and C, atypical morphology and 11q deletion. On univariate analysis of survival estimates, advanced Binet stages, CD38+ phenotype, atypical morphology and 11q or 17p deletions were associated with shorter event-free survival (EFS), treatment-free interval (TFI) and overall survival (OS). Multivariate analysis identified both Binet stages and CD38 as independent prognostic factors with regard to EFS and TFI. However, CD38 appeared as an independent factor for OS when restricted to Binet stage A. Chromosomal aberrations were re-evaluated during evolution in 31 cases. The 17p deletion was the most frequent new chromosomal abnormality (35%) and significantly associated with death (64%). In conclusion, CD38 expression and secondary 17p deletion are important poor prognostic indicators, especially in Binet stage A CLL.

ADP-ribosyl Cyclase↗
PubMedDate not supplied

[Maternal and obstetrical risk factors of placental vascular pathology (biologic and epidemiological data excluded)].

The purpose is to identify maternal and prenatal risks factors for placental vascular disorders. We excluded biologic and epidemiological data which are discussed in another chapter. Maternal risks factors are pre-existing vascular systemic diseases. Systemic lupus erythematosus (antiphospholipid antibodies are studied in another chapter) is a classical disease associated with unfavorable outcome, particularly when the disease is not quiescent and if the patient has a history of previous poor outcome. Obstetricians' awareness of the influence of inflammatory bowel diseases on pregnancy and fetal outcome is quite poor. These diseases, if they are not quiescent, can induce deleterious perinatal effects. Type 1 or even type 2 diabetes mellitus increases the risk of preeclampsia or hypertension in pregnancy, particularly when there is poor glycemic control early in pregnancy. The duration of type 1 diabetes affects the outcome of pregnancy more than type 2. Smoking during pregnancy is associated with many adverse events including spontaneous abortion, low birth weight and placental abruption. There are data about the dose-response relationship between the number of cigarettes smoked per day and the risk of abortion. Smoking during pregnancy is also protective against preeclampsia and this apparent paradox suggests the complexity of what is called vascular placental pathology. There is a significant relationship between pejorative perinatal vascular outcome and the non quiescence of renal disease. Mid-trimester uterine artery Doppler combining bilateral notches and increased uterine resistance index is the best criterion to predict the placental vascular risk of the pregnancy. Some promising studies suggest the feasibility of uterine Doppler ultrasound screening early in the pregnancy during the first trimester. Large studies are required to confirm this practice. Uterine artery Doppler in combination with other tests (elevated maternal serum hCG or ambulatory 24-hour blood pressure monitoring at 22 weeks gestation) could be a more efficient predictor of vascular complications. A large-scale evaluation is necessary before recommendations can be made. Multiple pregnancies increase the risk of preeclampsia 2- or 3-fold (RR 2.62; 95% CI: 2.03-3.38). A history of preeclampsia is the strongest predictor of unfavorable outcome for the second pregnancy.

Female↗